The present disclosure relates to systems and methods for quantitative ultrasound. More particularly, the present disclosure relates to systems and methods for diagnosing neuromuscular disease in a patient suspected of having a neuromuscular disease using quantitative muscle ultrasound.
Although ultrasound has been around since the 1950s, in recent years technology has evolved to the point that portable, relatively inexpensive, high resolution machines are more widely available, leading to widespread use in almost all fields of medicine. Ultrasound provides high resolution imaging of soft tissue, fascial planes, and neurovascular structures, allowing localization of muscle, nerve, and adjacent neurovascular or other vital structures. Use of real-time ultrasound guidance for needle placement during nerve conduction studies and needle electromyography (EMG) can increase accuracy and/or decrease risk in certain situations. Ultrasound can provide detailed anatomical and pathophysiological information in nerve and muscle disease as well as real time information related to muscle activation and movement patterns of nerve and muscle. Diagnostic ultrasound has been shown to have a significant role in the diagnosis of neuromuscular disorders, for example in identifying the underlying cause of various mononeuropathies and in screening for neuromuscular disease. Neuromuscular disorders result in muscle atrophy and intramuscular fibrosis and fatty infiltration, all of which can be visualized with ultrasound. Sensitivity and specificity of muscle ultrasound in the detection of neuromuscular disorders has been shown to be very high in several prospective studies.
In the pediatric population, ultrasound is a useful tool because it is painless, rapid, and does not carry any radiation risk. Nerve conduction studies and needle EMG are typically performed under conscious sedation in pediatric patients. This exposes children to the risk of anesthesia (which is of particular concern in patients with certain neuromuscular disorders) as well as increasing the cost of the study more than five fold. The EMG study itself is often technically difficult, in many cases the child is too sedated to activate the muscles to allow for motor unit analysis and the final diagnosis may be indeterminate. Also, sensitivity of EMG in hypotonic infants and particularly in myopathy in infants and children has been shown to be quite low.
In adults, many patients with symptoms of myalgia or subjective weakness are referred to an EMG lab to rule out myopathy or other neuromuscular disease. Though representing a patient population that can tolerate the EMG process better than the pediatric population, the invasive nature is still a substantial drawback to for the adult population.
Therefore, it would be desirable to have a system method for analyzing nerves in patients without the use of needles and processes such as EMG.